Conventionally, various types of so-called “underwear-type diapers” formed in a shape of briefs in advance have been proposed.
For example, FIG. 5 is a partially broken perspective view of a disposable underwear-type diaper 1. As shown in FIG. 5, the underwear-type diaper 1 is formed in an underwear shape where the upper parts of an abdomen side 8A and a back side 8B of a body 8 are connected by a pair of fasteners 40, and has a waist opening 5 and a pair of leg openings 6.
The body 8 includes a liquid transmitting top sheet 2 that is in contact with the skin of the wearer, a liquid non-transmitting back sheet 3, and an absorber 4 disposed between the top sheet 2 and the back sheet 3. The absorber 4 is disposed on the wearer's abdomen side and back side.
In the fastener 40, an abdomen side fastening piece 40A and a back side fastening pieces 40B are bonded together at a joint 41. The abdomen side fastening piece 40A includes a body 42 and a tape portion 43 where a tab 45 for nipping is formed. The tape portion 43 is detachably fixed to a target zone 44 fixed to the back sheet 3.
Since the disposable underwear-type diapers 1 are continuously produced, for example, by production steps schematically shown in FIG. 6, the abdomen side fastening piece 40A and the back side fastening pieces 40B are bonded together at the joint 41.
That is, as shown in FIG. 6, while a belt-like top sheet continuous body 52 for forming the top sheet 2 and a belt-like back sheet continuous body 53 for forming the back sheet 3 are conveyed in the directions of the lengths thereof as shown by the arrows, the absorber 4 conveyed in synchronism is disposed between the top sheet continuous body 52 and the back sheet continuous body 53, thereby forming a diaper web continuous body 51.
To the diaper web continuous body 51, fastening piece members 40A′ and 40B′ for forming the fastening pieces 40A and 40B are alternately fixed in the conveyance direction. Specifically, after a target zone member 44′ for forming the target zone 44 is fixed to the surface of the back sheet continuous body 53, the tape portion 43 of the fastening piece member 40A′ is pasted to the target zone member 44′. To a predetermined position of the top sheet continuous body 52, the fastening piece member 40B′ is fixed.
Then, as shown at reference designation c, the diaper web continuous body 51 is cut in the direction of the width at a position where the fastening piece members 40A′ and 40B′ are divided in two, thereby forming a diaper web 50 to which the fastening pieces 40A and 40B are fixed.
Then, as shown at reference designation d, the diaper web 50 is folded in two along an imaginary line in a direction orthogonal to the direction of the flow thereof, and the side edges of the fastening pieces 40A and 40B facing each other are bonded together to form the joint 41.